The Mariners made several roster moves prior to Wednesday's game against the the Chicago White Sox.
The team also recalled outfielder Norichika Aoki and catcher Mike Zunino from Triple-A Tacoma. Left-hander David Rollins, outfielder Daniel Robertson and catcher Jesus Sucre were optioned to Tacoma after Tuesday night's game.
Hernandez was the scheduled to start Wednesday's game, his first start since May 27.
Hernandez, 30, is 4-4 with a 2.86 ERA over 63 innings this season, with 53 strikeouts and 26 walks in 10 starts. Hernandez was placed on the 15-day disabled list with a right calf strain on June 1 (retroactive to May 28). In two rehab starts with Class A Everett and Tacoma, Hernandez was 1-0 with a 3.86 ERA over 9 1/3 innings, with 13 strikeouts and three walks.
In his 12th major league season with the Mariners, Hernandez is the all-time club leader in wins (147), strikeouts (2,195), starts (344) and innings pitched (2,325 1/3).
Aoki, 34, hit .369 with four RBIs in 16 games with Tacoma. He hit safely in 11 of 16 games with Tacoma, including recording eight multi-hit contests. Before being optioned to Tacoma on June 24, Aoki hit .245 with 11 RBIs in 67 games with Seattle.
Zunino, 25, hit .286 with 17 home runs and 57 RBIs in 79 games with Tacoma. He appeared in two games with the Mariners, hitting two home runs.
Rollins, 26, is 1-0 with a 4.05 ERA over 6 2/3 innings with five strikeouts and six walks in eight relief appearances over three stints with the Mariners this season.
Robertson, 30, hit .263 with one RBI in nnie games with Seattle. Prior to being selected from Tacoma on July 5, Robertson hit .262 with four home run and 25 RBIs in 73 games with Tacoma this season.
Sucre, 28, hit .125 in three games with Seattle. Prior to being activated from the 60-day disabled list on July 6, Sucre combined to hit .241 with four RBIs in nine games on a rehab assignment. He was placed on the 60-day disabled list on March 1 after having surgery to repair damage in his right ankle on Jan. 26, 2016. He sustained a fractured right fibula during winter ball in Venezuela on Jan. 17.